Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
va nay » va ngay, va cay
xuc va » duc va, tuc va, luc va
vi cua » vai cua, di cua
o hoi » co hoi, o hai, o hoa
o hoc » co hoc, mo hoc, so hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((((o hoi) OR (o hoc))) or (xa hoi)). lieu va nay xuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((((o hoi) OR (o hoc))) OR (xa hoi)). lieu va nay xuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((((o hoi) OR (o hoc))) or (xa hoi)). lieu va nay xuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((((o hoi) OR (o hoc))) or (xa hoi)). lieu va nay xuc va hanh vi cua tre*.